This relates generally to imaging systems, and more particularly to imaging systems for error-sensitive applications such as automotive applications.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Imagers (i.e., image sensors) may be formed from a two-dimensional array of image sensing pixels. Each pixel receives incident photons (light) and converts the photons into electrical signals. Image sensors are sometimes designed to provide images to electronic devices using a Joint Photographic Experts Group (JPEG) format.
In a system that incorporates image sensors, data from the sensors typically flows through multiple electronic sub-systems, which may either be co-located on the image sensor, or external to the sensor. Such systems can fail spontaneously in the field due to effects such as electromigration or cosmic radiation. Imaging systems that are used in error-sensitive applications such as advanced driver assistance systems (ADAS) or self-driving cars have limited tolerance for incorrect operation, and current automotive safety standards, such as ISO-26262, mandate that systems include the capability to detect failures that could create hazardous situations. Consider the scenario in which image data from an image sensor is used to control an adaptive cruise control function or automatic braking function. In this scenario, incorrect image data from the image sensor that does not accurately reflect reality can be a safety hazard (e.g., malfunction of the adaptive cruise control or automatic braking).